Method of shelling nuts



July 8, 1941. A. s. LEONARD E'r AL METHOD OF SHELLING NUTS 3Sheets-Sheet 1 Filed Feb. 27. 1940 w m n w.

ATTORNEY July 8, 1941. A. s. LEONARD ETAL METHOD oF SHELLING NUTS FiledFeb. 27, 1940 3 Sheets-Sheet 2 INVENTORS.

Q ,..j v N Mu BY @Ya/n? A TTORNEYl July 8, 1941-. A. s. LEQNARD ETAL2,248,365

METHOD OF SHELLING NUTS Filed Feb. 27, 1940 3 sheets-sheet 3 A TTORNEYPatented July 8, 1941 UNITED STATES PATENT oFricE METHOD or snELLlNGNU'rs Berkeley, and Harry B. assignors to The Regents -of the Universityof California, Berkeley, Calif., a corporation of California ApplicationFebruary '21, 194e, serial No. 321,020

(ci. 14e-219) Arthur S.

Walker, Davis, C

Claims.

This invention relates in general to the art of breaking and -removingthe hard outer covery ing of a nut, or similar object, andparticularlyto a method for shelling nuts in which combusf tion of an explosive uidmixture is utilized to break and remove the hard shell therefrom. Thepresent joint application is for the same invention as that set forthand claimed in the copending sole application of Harry B. Walker,

iiled November 14, 1938, Serial No. 240,223, entitled Method andapparatus for shelling nuts.

In the past, various types of mechanical devices have been devised toremove the shells from nuts, such as walnuts, but they have generallyproved unsatisfactory. Such prior devices have generally been operatedto apply a compressive force to the external surface of the nut shell tobreak the shell, and separate means have been provided. for separatingthe shell from the kernel. The operation of such devices has been slow,inefllcient and impractical. it being impossible to provide a suitablebreaking pressure for nut shells of varying degrees -ofA hardness, withthe undesirable result that .the kernels of the nuts are frequentlybroken or damaged. It is therefore a primary object of this invention toprovide a method forv continuously shelling nuts at a high rate of speedand'without damaging the kernels thereof.

It has been found that by applyingv a substantially uniform, outwardlydirected force on the interior surface of a nut shell. the shell can bebroken and removed from the nut without damaging the kernel therein. Inthe operation of this method, it has been possible to remove the shellsfrom oversixty per cent of the nuts treated thereby. without damaging orbreaking the kernel. It is therefore a further object of this inventionto provide a method for subjecting .the shell of a nut to a suddenlyapplied outwardly directed pressure diierential suilicient to break theshell and remove it from the nut kernel within.

Another object of the invention is to provide a. method for breaking orremoving a shell from a nut which consists in perforating the nut,introducing a combustible uid into theA nut through the perforation, andthen igniting the mixture to break and remove the shell.

A suitable type of apparatus which has been successfully employed incarrying out this method is shown in the accompanying drawings, whichare submitted for purposes of illustration only, as 'the apparatus formsthe subject matter of a co-pending application. In the drawings,

Fig. 1 is an. elevational view partly in section of the apparatus:

IFig. 2 is a plan view of the apparatus shown in Fig. 1, showing thehood 'I5 removed;

Fig. 3 is an end view of the machine looking at the discharge endthereof, said View showing the ring burner and hood l5 removed:

Fig. 4 is an enlarged cross-section taken on line IV-IV of F18. 2;

Fig. 5 is an enlarged cross-section taken on line V--V of Fig. 2; and

Fig. 6A is a side elevation of a walnut showing the manner ln which itis cut by the saw.

Refen'lng to the drawings, a support I0 is shown, which may be a tableor bench or other suitable supporting surface having rigidly securedthereto vertically disposed supporting columns II and I2, respectively,having their upper ends drilled to journal axles I5 and I6 of hat pulleywheels i1 and I8.

Secured to the other end of the support I0 are similar upright supports2li and 2|, shown in detail in Fig. 3, and which are aligned with thesupporting columns I I and I2 as shown in Fig. 2. The upright supports20 and 2i are each formed with an open frame 22 suitably secured to thesupport I0, each frame having a top cross bar 23 which supports abearing 24. Journaled in the bearing 24 ofthe upright support 20 is ashaft 25, and :lournaled in the bearing 2l of the upright support 2| isa shaft 26. each of the shafts being connected through suitable bevelgearing 21 to a transverse shaft 28 which is connected, through areduction gear box 29 of the type well known in the art, to an electricmotor 30 by a suitable belt and pulley structure 3l. The upper end ofthe shaft 25 has rigidly fixed thereto a drive pulley 33, and the shaft26 has iixed thereto a second drive pulley 3l. The drive pulley 33 isoperatively connected to the pulley wheel I1 by a at belt 3B, and thedrive pulley 34 is connected to the pulley wheel I8 by a ilat belt 38.The belts 35 and 3B are` identical in construction and may be formedfrom any suitable material. Each belt is4 faced withfor the drivepulleys 33 and 34 is so arranged, as is well known in the art, to rotatethe drive pulleys in opposite directions so as to move the adjacentportions of the belts 35 and 35 in the same direction. i

Also secured to the support l are standards 39 and 40 having slots 4|and 42 therein, respectively. Connected to .the standards 39 and 40 andsupported thereby is a sub-base 43 having suitable bolts which projectthrough the slots 4| and 42,'being secured to the standards by means ofnuts 44 and 45 provided therefor. It is to be noted that by looseningthe nuts 44 and 45, the sub-base 43 may be raised or lowered to anydesired height within the limits of the slots 4| and 42. Fixed to thesub-base 43 is an electric motor 46 having a drive shaft 41, on the endf which is secured a circular saw member 48 of the type well known inthe art. Also secured to the sub-base 43, as by bolts 49 and 50, is atrack element |y which, as shown in Figs. 1 and 2, extends from a pointadjacent the circular saw member 48 to a point substantially between theshafts 25 and 25. The track element 5| is provided with a longitudinalbead 52 which extends the length thereof. It will be noted that thecircular saw member 48 and the longitudinal bead 52 are in alignment andare positioned approximately midway between the adjacent portions of thebelts 35 and 35. Connected to the left end of the track element 5|, asseen in Figs. 1 and 2. is a chute member 53 inclined downwardlytherefrom and which may be made either V-shaped or semi-cylindrical. Theend of the chute member 53 is provided with a semi-circular guard plate54 which is positioned directly above an ignition means generallydesignated at 55.

A plurality of upwardly venting ports 55 are provided in thelongitudinal .bead 52, and, as shown in Fig. 1, are connected bysuitable piping 56 to a source of combustible fluid,not shown. It hasbeen found desirable to use a combustible fluid comprising acetylene andoxygen in a suitable mixture, and to provide a mixing valve 51 in theline of the piping 56 in which the oxygen and acetylene may be mixed insuitable proportions. but it is t0 be understood that the invention isnot limited to the use of such a combustible fluid, and that thereforeit may be desirable to dispense with the mixing .valve 51 if some othertype of fluid is employed.

In operation, the electric motor 35 is enerirized to rotate the drivepulleys 33 and 34 so as to move the adjacent portions ofthe belts 35 and38 in a direction toward the chute member 53. The electric motor 46 isalso energized so as to rotate the circular saw member 43 at high speed.Nuts. such as walnuts. are then introduced in sequence from the i'eedytable 31 and are engaged by the belts 35 and 38 and carried therebetweeninto contact with the circular saw member 48 which cuts ashallow slot 15therein. as shown in Fig. 4. The nuts are then oonveyed onto the trackelement 5|, the longitudinal bead 52 entering and closing the slot 13 soas to temporarily seal the slot in each nut. 'Ihe combustible fluid,such as a mixture of acetylene and oxygen, as above mentioned,isconveyed through the piping 55 to the ports 55. and as each nut passesover these ports it receives a charge of the combustible mixture, theslot immediately thereafter being again sealedy by the longitudinal bead52 for the balance of the travel of the nut along the track element 5|.As each nut comes to the end of the track element 5|, it falls free ofthe belts 35 and 33 into the downwardly directed chute member 53,hitting the semi-circular guard plate 54 and then dropping verticallydownward into the fiame/ maintained by the ring burner 55. As each nutenters the upper zone of the name, the combustible fluid mixture in thenut is ignited. An explosion of sufficient force to shatter the shellimmediately takes place, with the result that' the shell bursts intofragments which are thrown outwardly in the direction of arrows a (seeFig. 1), while the meat or kernel of the nut is left intact and dropsdown in the direction of arrow b through the ring burner into areceptacle 5|.

An exterior container 52 receivesY the shell fragments, and acomparatively clean separation of shell fragments and kernels results.Final cleaning of the kernels to remove any foreign matter is thusreadily accomplished.

In actual practice, a small quantity of gas will escape from the ductsB5 whenever they are uncovered by the nuts.4 Also, a small quantity ofgas will escape from the nuts themselves as they roll or slide down thetrough 53`.` To prevent any ill eifect or annoyance to the operators, ahood 15 is extended over the machine. This hood is connected through apipe 15 with the suction side of a blower, not here shown. -A continuoussuction is thus maintained under the hood, which will insure continuousremoval of the escaping gas and also the products of combustion from theburner ring, and a clean, uncontaminated atmosphere is thus maintainedabout theA machine.

While the slot or cut made in each nut by the circular saw may be madein any part of the shell, it is preferable'to feed or deliver the nutsbetween the belts with the longitudinal axis indicated by the dottedline 35-33 (see Fig. 6) pointing in the direction of travel of thebel-ts. Also it is preferable that the ridge-3| surrounding the nutshould assume a substantially horizontal position, as shown in Figs. 4and 5, as

the thinnest portion of the shell will inY this manner be presented tothe saw; Obviously, if the nut were presented so that the saw would haveto cut through the ridge, more resistance would be encountered, andwhile it is not of great importance one way or another, it would bepreferable to feed the nuts in the manner described. Plainly speaking,the nuts may be fed between the belts in any position. as, no matter howthey are presented to the saw. the saw will slit them. In fact, one ofthe features of the machine is that exact positioning of the nuts is notnecessary. In the presen-t instance, the nuts are hand-fed from the feedtable. Hence it is important that, no matter how the nuts arereceivedthe saw must act on them. but obviously as an operator becomesexperienced, positioning of the nuts to proper advantage will sooner orlater become ahabit.

`assume a fixed position with relation to the saw when they pass thesame, as adjustment of the saw would otherwise be to no avail. The feedtable assures such positioning; that is, the feeder merely pushes thenuts along the table surface until they are gripped between the belts.Thus, the lower face of each nut is maintained at a xed elevation withrelation to the saw, and the saw can be raised or lowered to increase ordecrease the depth of the cut.

When a nut is engaged by the saw, there is an upward thrust. Hence,means must be provided for preventing upward movement of the belts andthe nuts gripped between them as they pass under the saw. This isaccomplished by providing side guides 82 and flange guides 83 (see Figs.2 and 4). These side guides extend from a point adjacent the saw to apoint adjacent the discharge end of the machine, as shown in Fig. 2. Theange guides 83 are disposed -at a point adjacent the saw. These flangesprevent an upward thrust of the belts and nuts when passing the saw,while the remaining portions of the side guides prevent spreading of thebelts until the point for discharging the nuts is reached.

Although a hand feed has been described, an automatic feed may obviouslybe employed. The faster or more rapidly the nuts are fed, the better themachine operates, as the escape of gas from the orifices S5 will bereduced, as will the escape of gas from the nuts after they have beencharged with gas.

In actual practice the pulley supports II--IZ and 2li-2| will belaterally adjustable to vary the spacing between the parallel belts sothat nuts of varying size may be accommodated. This lateral adjustmentis very desirable, since it requires considerable lateral pressure fromthe rubber-faced belts against the nuts to hold them sufficiently rigidwhile they are being cut by the saw. If a very large nut should befollowed by a small nut, there would obviously be difculty. Accordingly,in a cracking plant the nuts would be graded to size and the machinewould be adjusted to the required distance between the parallel belts toinsure suicient pressure to hold the nuts rigid during the sawingoperation. Lateral adjustment may be obtained in various ways, a simplemethod being to form slots 92 in the table l or in the flanges of thebearing standards through which the fastening bolts extend, these slotsbeing of sufficient length -to permit the required lateral adjustment.

While certain features of the present invention have been more or lessspecifically described and illustrated, it is nevertheless to beunderstood that changes may be resorted to Within the scope of theappended claims.

Having thus described and illustrated the invention, what we claim anddesire \to secure by Letters Patent is:

1. A method of breaking the shell of a nut including the steps ofintroducing an explosive in gaseous form inside the shell of the nut inthe space between the kernel and the shell, and immediately thereafterigniting the explosive to explode the same and burst the shell withoutsubstantially injuring the kernel.

2. A method of breaking the shell of a nut including the steps ofperforating the shell so as to form an opening communicating with theinterior thereof, introducing an explosive gas mixture into the shellthrough the opening into the space between the kernel and the shell, andimmediately thereafter igniting the gas mixture to explode the same andburst the shell without substantially injuring the kernel.

3. A method of breaking the shell of a nut including the steps of:perforating the shell so as to form an opening communicating with theinterior thereof; introducing an explosive gas mixture into the shellythrough the opening into the space between the kernel and the shell,substantially sealing said opening for a short period to prevent theescape of the gas mixture through said opening, and immediatelythereafter igniting the gas mixture to explode the same and burst theshell without substantially injuring the kernel.

4. The method of shelling nuts which comprises cutting an opening in theshell, introducing an explosive gas mixture into the shell through theopening into t-he space between the kernel and the shell, preventingescape of the gas mixture through said opening, and immediatelythereafter igniting the gas mixture to explode the same and burst theshell Without substantially injuring the kernel.

5. A method of shelling a nut which comprises perforating the shell toform an opening communicating with the interior of the shell,introducing an explosive gas mixture through said opening into the spacebetween the shell and the kernel, and immediately thereafter passing thenut through a flame area to ignite the gas and to explode and burst theshell without substantially injuring the kernel.

ARTHUR S. LEONARD. HARRY B. WALKER.

